Toilet cistern dual flush valve

ABSTRACT

The invention provides a toilet cistern dual flush valve ( 10 ) operable selectively in a full flush mode in which a relatively large volume of water is discharged from the cistern or a partial flush mode in which a relatively small volume of water is discharged from the cistern. The dual flush valve ( 10 ) comprises a stem ( 36 ) carrying a valve closure ( 38 ) seatable on an outlet from the cistern, means to raise the stem ( 70, 72,74 ), buoyant means ( 50 ) attached to the stem ( 36 ) which in the full flush mode maintains the stem ( 36 ) in the open position until the relatively large volume of water has been discharged and the buoyant means ( 50 ) loses buoyancy whereafter the stem ( 36 ) descends under gravity to the closed position, and means ( 54 ) which operates in the partial flush mode to add sufficient mass to the stem when the relatively small volume of water has been discharged causing the stem ( 36 ) to descend to the closed position.

BACKGROUND TO THE INVENTION

[0001] THIS invention relates to a toilet cistern dual flush valve whichis capable of discharging different volumes of water from the cistern atthe election of the operator.

[0002] Toilet cisterns generally have a fixed volume of water, the fullcontent of which is discharged to the toilet bowl when flushing isinitiated. In many instances, a full discharge is not required andeffective flushing of the toilet bowl could be achieved by discharging asmaller volume from the cistern. In this way wastage of water could beminimised resulting in reduced water consumption and associated costs tothe consumer.

[0003] A number of dual flush toilet cistern valves have been devisedwith a view to providing the user of the toilet with a choice between afull flush in which the full content of the cistern is discharged intothe toilet bow), and a partial flush in which only part of the cisterncontent is discharged. Many of the known dual flush valves are eithercomplicated and expensive to manufacture or are unreliable in operation.Another problem with some known dual flush valves is their use of twoseparate floats each at the end of a relatively long, transverse floatarm to achieve selective locking of a valve stem carrying the valveclosure which controls the discharge of water from the cistern to thebowl. The long float arms make such valves unsuitable for use in thecompact cisterns which are currently in favour. The present inventionseeks to provide a compact, simple and relatively inexpensive dual flushvalve.

SUMMARY OF THE INVENTION

[0004] According to the invention there is provided a toilet cisterndual flush valve operable selectively in a full flush mode in which arelatively large volume of water is discharged from the cistern or apartial flush mode in which a relatively small volume of water isdischarged from the cistern, the valve comprising;

[0005] a valve stem carrying a valve closure seatable on an outlet fromthe cistern and movable between a raised, open position in which theclosure is spaced from the outlet and a lowered, closed position inwhich the closure seats on the outlet,

[0006] means operable in both full and partial flush modes to raise thestem,

[0007] operatively buoyant means attached to the stern which in the fullflush mode maintains the stem in the open position until the relativelylarge volume of water has been discharged and the buoyant means losesbuoyancy whereafter the stem descends under gravity to the closedposition, and

[0008] means which operates in the partial flush mode to add sufficientfurther mass to the stem when the relatively small volume of water hasbeen discharged, to cause the stem to descend to the closed position.

[0009] A preferred embodiment of the invention includes actuators whichare selectively, manually operable to initiate the full or partial flushmode, an upper float unit, upper and lower collars on the stem, andlinkages extending between the actuators and the upper float unit suchthat operation of either actuator raises the upper float unit intoabutment with an upper collar on the stem thereby raising the stem tothe open position. The linkages may include a toggle attached pivotallyto the upper float unit and carrying a detent, the arrangement beingsuch that operation of the relevant actuator to initiate a partial flushcauses the toggle to pivot to a position in which the detent engages thelower collar and adds the mass of the upper float unit to the stem whenthe water in the cistern has dropped to a level at which the upper floatunit loses buoyancy. The upper float unit may include a water reservoirto accommodate a volume of water providing gravitational mass.

[0010] Both the main float and the upper float unit may include invertedcup-shapes to accommodate air which renders both the main float andupper float units buoyant in water.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention will now be described, by way of example only, withreference to the accompanying drawings in which:

[0012]FIG. 1 shows a partially exploded perspective view of a dual flushvalve according to this invention;

[0013]FIG. 2 shows a side view of the stem, main float and closureassembly of the dual flush valve of FIG. 1;

[0014]FIG. 3 shows a side view of the secondary float unit of the dualflush valve of FIG. 1;

[0015]FIG. 4 shows a side view of relevant components of the dual flushvalve of FIG. 1 when a full flush is initiated;

[0016]FIG. 5 shows a vertical cross-sectional view of relevantcomponents of the dual flush valve of FIG. 1 when a partial flush isinitiated;

[0017]FIG. 6 shows a horizontal cross-section at the line 6-6 in FIG. 4;

[0018]FIG. 7 shows a horizontal cross-section at the line 7-7 in FIG. 5;

[0019]FIG. 8 shows a side view of a second embodiment of the dual flushvalve according to the invention;

[0020]FIG. 9 shows an exploded perspective view of components forsuspending the dual flush valve of FIG. 8 in a cistern; and

[0021]FIG. 10 shows a perspective view of actuating buttons of the dualflush valve of FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0022]FIG. 1 shows a dual flush valve 10 according to this invention.The valve 10 includes an outlet structure 12 having a threaded spigot14, a nut 16 mateable with the spigot, a flange 18 and three legs 20extending vertically from the flange and carrying enlargements 22 attheir upper ends.

[0023] The valve 10 also includes a housing 24 of generally inverted cupshape. The housing has a cylindrical skirt 25 carrying circumferentiallyspaced locking formations 26 and an annular upper wall 28 from which acylindrical sleeve 30 projects vertically.

[0024] When installed in a toilet cistern 31 the spigot 14 is passeddownwardly through an opening in the base 33 of the cistern and theoutlet structure 12 is locked in place by engaging the nut 16 with thespigot beneath the base. The housing 24 is then located over the outletstructure 12 with the enlargements 22 received through enlarged zones 32of the locking formations 26. The housing is then rotated relative tothe outlet structure to locate the enlargements 22 over relativelynarrow zones 34 of the locking formations 26. It will accordingly beunderstood that the housing 24 is locked to the outlet structure 12 bywhat is, in effect, a bayonet action.

[0025] The dual flush valve 10 also includes a vertical, hollow stem 36carrying a closure 38 at its lower end which can seat on the rim of theoutlet opening 40 through the outlet structure 12. The stem passesslidably through the sleeve 30 of the housing 24 and carries arelatively large collar 42 and a relatively small collar 44 at spacedapart positions near to its open upper end. Beneath the upper wall 28 ofthe housing the stem passes through, and is fixed to, a central sleeve46 extending downwardly from the horizontal upper wall 48 of a mainfloat 50. The float 50 is in the form of an inverted cup and has acylindrical skirt 52 depending downwardly from the periphery of theupper wall 48. The outside diameter of the float skirt 52 is somewhatless than the inside diameter of the housing skirt 25 so the float 50,which is fixed to the stem 36, is capable of free vertical movementwithin the housing.

[0026] Another component of the valve 10 is a secondary or upper floatunit 54 which has an upper cup-shaped reservoir section 56, a lowerfloat section 58 of inverted cup-shape and a horizontal wall 60 servingboth as a base of the section 56 and an upper wall of the section 58. Acentral, vertical sleeve 62 extends upwardly from the wall 60. The stem36 extends freely through this sleeve which has an internal diametergreater than the external diameter of the lower collar 44 but smallerthan the external diameter of the upper collar 42. The upper edge of thesleeve 62 is formed with a cut-out 64 shaped as shown in FIG. 3.

[0027] Pivoted externally to the side of the sleeve 62, at a pivot axis66 located generally beneath the cut-out 64, is a toggle 68 having theshape of a sector of a circle. The upper edge of the toggle carries adetent 70 which projects transversely into the cut-out 64 in a directiontowards the stem 36.

[0028] Attached pivotally to the toggle at spaced apart points onopposite sides of the pivot axis 66 are upright arms 72 and 74. At theirupper ends, the arms 72 and 74 are pivoted to respective transverse arms76 and 78. The arm 76, which is a full flush arm, extends from a collar80 fixed on a hollow shaft (not shown) which in use extends through thefront wall 81 of the cistern and to which a full flush actuating handle82 is connected. The arm 78, which is a partial flush arm, extends froma collar 84 fixed on a shaft 85 which extends rotatably through thehollow shaft and to which a partial flush actuating handle 86 isconnected. An element 88 extends from the collar 84 and overlies thecollar 80.

[0029] When the valve 10 is installed in the cistern in use, theactuating handles 82 and 86 are located externally on the front wall 81of the cistern for selective operation by the user. When the full flushactuating handle 82 is depressed, i.e. pivoted in a clockwise directionas illustrated, the hollow shaft to which it is attached will rotate ina clockwise direction, thereby raising the arm 72 via the collar 80 andfull flush arm 76. Because of the presence of the element 88, thisaction also rotates the collar 84 and hence the shaft 85 to which thepartial flush actuating handle 86 is connected. As a consequence, thearm 74 is also raised via the partial flush arm 78. The arms 72 and 74apply balanced lifting forces to opposite sides of the toggle 68 whichis itself lifted but does not rotate.

[0030] When the partial flush actuating handle 86 is depressed, theshaft to which it is connected rotates accordingly. The arm 74 istherefore raised via the collar 84 and partial flush arm 78. However inthis case, there is no corresponding movement of the arm 72. The arm 74applies an unbalanced force to the toggle and causes it to pivot, in ananticlockwise direction as viewed in FIG. 1, on the axis 66. The detent70 moves to a position in which it extends directly towards the axis ofthe stem 36.

[0031] The operation of the dual flush valve 10 will now be explainedwith reference to a full flush action and a partial flush action. Inboth instances a flushing action will commence when the cistern is fullof water, volumes of air are trapped in the main float 50 and in thefloat section 58 of the upper float unit 54, the reservoir section 56 ofthe upper float unit is full of water, and the valve closure 38 isseated in sealing manner on the rim of the outlet opening 40.

[0032] Full Flush

[0033] As just explained a full flush is initiated by depressing andthen releasing the actuating handle 82. Depression of the actuatinghandle has the effect of raising both arms 72 and 74. Because the toggle68 is attached to the upper float unit 54 at the pivot axis 66, theupper float unit is pulled upwardly. When the upper edge of the sleeve62 encounters the upper collar 42 on the stem 36, the stem is alsoraised. This lifts the valve closure 38 off the rim of the outlet 40,allowing water to discharge from the cistern through the spigot 14 andinto the toilet bowl to perform a flushing action. During flushing thestem is kept in a raised position by the buoyancy of the main float 50,attributable to the pocket of air trapped therein. Flushing willcontinue until the water level in the cistern has dropped to a levelwhere the float 50 loses buoyancy, allowing the stem 36 and with it theclosure 38 to drop. The closure reseats on the rim of the outlet opening40, thereby closing the valve again.

[0034] The upper float unit 54 is kept in a raised position during aninitial part of the full flush by the air pocket trapped in the lowerfloat section 58. When the water level in the cistern drops beneath thelower edge of the float section 58, the float unit 54 will descend withthe water level until it eventually comes to rest on the upper wall 28of the housing 24. As described previously, the stem 36 and closure 38are kept in the raised position by the buoyancy of the main float 50until the full flush is completed

[0035] It is to be noted that because the toggle does not pivot when thefull flush is initiated, the detent 70 remains in a position off-setlaterally from the axis of the stem 36, and so does not interfere withthe collar 44, as shown in FIG. 6.

[0036] Partial Flush

[0037] The partial flush is initiated by depressing the actuating handle86. As described previously, this has the effect of raising the arm 74only. The unbalanced force on one side of the toggle causes the toggleto pivot as it is pulled upwardly by the arm 74. As in the full flushmode of operation, the upper edge of the upper float unit 54 encountersthe upper collar 42 and raises the stem 36 and closure 38, initiatingthe flush. However in this case, the pivotal movement of the togglealigns the detent 74 with the axis of the stem, with the result that thedetent locates over the collar 44, as shown in FIG. 7.

[0038] As in the full flush mode the stem 36 is kept raised and theclosure 38 remains in an open position because of the buoyancy of themain float 50. The upper float unit is also kept raised by the buoyancyattributable to the air pocket trapped in the float section 58.

[0039] When a partial flush has taken place, the water in the cisternhas dropped to the level of the lower edge of the float section 58. Atthis point, the float unit 54 loses buoyancy and starts dropping.Because the detent 70 has located over and moves into contact with thecollar 44, the gravitational force on the float unit 54 is transferredto the stem 36. While the unit 54 is itself relatively light, its massis considerably increased by the volume of water in the reservoirsection 56. The combined mass of the float unit 54 and the volume ofwater in the reservoir section is sufficient to overcome the buoyancy ofthe main float 50, so the stem is forced downwardly for the closure 38to reseat on the rim of the opening 40 and close the valve. At thisstage, only a part of the cistern contents have been discharged.

[0040] As the float unit 54 drops the toggle 68 is reset to a neutral orbalanced position, in which the detent is free of the collar 44, by theupward force on the toggle applied by the arm 72.

[0041] In both the full and partial modes of operation, the cistern isrefilled in the normal way via a cistern inlet valve which forms no partof the present invention and which is not shown in the drawings.

[0042] The design of the valve 10 described above is suitable for use inmodern, compact toilet cisterns in which internal space is at a premium.It will also be appreciated that the valve 10 is of sufficiently simpleconstruction to enable it to be manufactured at relatively modest cost.

[0043] A feature of the design is the use of the mass of water in thereservoir section 56 to apply a valve closing force in the partial flushmode. It is however within the scope of the invention for the requiredmass to be provided by, for instance, a weight attached to the floatunit, although this would increase the overall cost of the valve.

[0044] A second embodiment of a dual flush valve is depicted in FIG. 8and indicated by the reference numeral 110. In this instance actuatingbuttons 112 and 114 replace the pivoted actuating handles 82 and 86 onthe front wall of the cistern as described in the first embodiment.

[0045] The actuating buttons 112 and 114 are clearly illustrated in FIG.10. It will be noted that they have flat portions at their sidesallowing them to be placed juxtaposed within the flat portions facingone another.

[0046]FIG. 8 shows that the actuating buttons 112 and 114 are located ina sleeve 118 and are moveable relative to each other in the sleeve 118.It will be noted that the sleeve is a carried by a support beam 120.

[0047] The support beam 120 is suspended within the cistern by twobrackets 122 and 124. The connection between the support beam 120 andthe brackets 122 and 124 is illustrated in FIG. 9. The support beam 120has a tongue 126 locatable in a cavity 128 of the bracket 122. Once thetongue 126 is located in the cavity 128, it can be secured with a bolt134, shown in FIG. 8, that is placed through holes 130 and 132 which arelocated in the tongue 126 and the bracket 122 respectively. The supportbeam 120 is connected to the support bracket 124 in a similar manner.

[0048] Various different options are available for suspending thebrackets in position. FIG. 9 illustrates one possibility in which thebracket 122 has two protruding members 136 and 138 at its ends. Theprotruding member 136 is slidably locatable in a slot 140 defined by asupport frame 142 that is attached to the inside of the front wall (notillustrated) of the cistern with adhesive. The protruding member 138 isattached to the back wall of the cistern in a similar fashion. Placingthe cistern's lid in position will prevent the protruding members beingremoved from their respective slots.

[0049] It is envisaged that slots similar to the slot 140 can be formedin the walls of the cistern itself. However, the dual flush valve 110should also be capable of use in existing cisterns and in suchsituations will require the use of frames as described above.

[0050] Turning again to FIG. 8, it will be noted that the sleeve 118 hastwo lugs 144 and 146 connected thereto, each support frame having apivot pin indicated by the reference numerals 148 and 150 respectively.

[0051] The pivot pin 148 pivotally connects the button 112 via an arm151 with an arm 152, which is in turn connected to an arm 156. A portionof the arm 151 is located in a cavity 153 shown in FIG. 10. In operationthe linear movement of the button 112 in a downward direction will causethe arm 152 to pivot on the pivot pin 148 thereby moving the arm 156 inan upward direction. This movement, illustrated in broken lines in FIG.8, will initiate a partial flush as described previously. Depressingboth buttons simultaneously will lead to a full flush, also as describedpreviously,

[0052] A further feature of the second embodiment is also illustrated inFIG. 8. It is know that toilet cisterns are normally manufactured in twostandard sizes, i.e. 6 I and 9 I. In different embodiments of thesecisterns the height of the cistern may vary. From an economicperspective it would therefore be desirable if a single dual flush valve110 could be installed and used in cisterns having either of thesestandard sizes and varying cistern heights.

[0053] This objective is addressed by having arms 156 and 158 oftelescopic construction. Telescopic movement is achieved in that thearms 156 and 158 include ratchets 160 and 162 as well as catches 164 and166 respectively. Telescopic construction is well known in the art andit will suffice to say that each catch can be moved on the associatedratchet in such a manner that the effective length of the arms 156 and158 can be either increased or decreased depending on the cistern size.

[0054] In FIG. 8 both the lower float section 58 of the upper float unit54 and the float 50 are filled with closed cell foam. It has beenmentioned that the floats 50 and 54 are kept in a raised position due tothe buoyancy attributable to air pockets trapped therein. Using closedcell foam manufactured air pockets trapped therein will lead to a moreconstant degree of buoyancy of the floats thereby enhancing the overallperformance of the dual flush valve 110.

[0055] As indicated previously, the stem 36 is hollow. Its open upperend serves as a cistern overflow to allow water to escape from thecistern in the event of overfilling. In another modification, the stemcould be of telescopic construction to allow its upper end to be raisedor lowered to suit a particular cistern and the desired flush volume.

1. A toilet cistern dual flush valve operable selectively in a fullflush mode in which a relatively large volume of water is dischargedfrom the cistern or a partial flush mode in which a relatively smallvolume of water is discharged from the cistern, the valve comprising: avalve stem carrying a valve closure seatable on an outlet from thecistern and movable between a raised, open position in which the closureis spaced from the outlet and a lowered, closed position in which theclosure seats on the outlet, means operable in both full and partialflush modes to raise the stem, operatively buoyant means attached to thestem which in the full flush mode maintains the stem in the openposition until the relatively large volume of water has been dischargedand the buoyant means loses buoyancy whereafter the stem descends undergravity to the closed position, and means which operates in the partialflush mode to add sufficient further mass to the stem when therelatively small volume of water has been discharged, to cause the stemto descend to the closed position.
 2. A toilet cistern dual flush valveaccording to claim 1 wherein the means operable to raise the stemincludes actuators that are selectively, manually operable to initiatethe full or the partial flush mode.
 3. A toilet cistern dual flush valveaccording to claim 2 wherein the actuators are actuating handles.
 4. Atoilet cistern dual flush valve according to claim 2 wherein theactuators are actuating buttons.
 5. A toilet cistern dual flush valveaccording to any one of claims 1 to 4 wherein the operatively buoyantmeans includes a main float.
 6. A toilet cistern dual flush valveaccording to any one of claims 1 to 5 wherein the means which operate inthe partial flush mode to add further mass to the stem includes an upperfloat unit.
 7. A toilet cistern dual flush valve according to any one ofclaims 1 to 6 wherein the valve stem includes upper and lower collars.8. A toilet cistern dual flush valve according to any one of claims 2 toclaim 7 including linkages extending between the actuators and the upperfloat unit such that operation of either actuator raises the upper floatunit into abutment with an upper collar on the stem thereby raising thestem to the open position.
 9. A toilet cistern dual flush valveaccording to claim 8 wherein the linkages include a toggle attachablepivotally to the upper float unit, the toggle including a detent suchthat operation of the relevant actuator to initiate a partial flushcauses the toggle to pivot to a position in which the detent engages thelower collar and adds the mass of the upper float unit to the valve stemwhen water in the cistern has dropped to a level at which the upperfloat unit loses buoyancy.
 10. A toilet cistern dual flush valveaccording to claim 9 wherein the upper float unit includes a waterreservoir to accommodate a volume of water to provide gravitationalmass.
 11. A toilet cistern dual flush valve according to any one ofclaims 5 to 10 wherein the main float and/or the upper float unitinclude inverted cup shapes to accommodate air.
 12. A toilet cisterndual flush valve according to any one of claims 5 to 10 wherein theinverted cup shapes of the main float and/or the upper float unitinclude closed cell foam.
 13. A toilet cistern dual flush valveaccording to any one of claims 7 to 12 wherein each linkage includes atelescopic construction to lengthen or shorten the linkage.
 14. A toiletcistern dual flush valve according to claim 13 wherein the telescopicconstruction includes a catch and a ratchet.
 15. A toilet cistern dualflush valve substantially as herein described and illustrated in thedrawings.